Select the two values of x that are roots of this equation

Solve the system by elimination.<br> -8X – 10y = 20<br> -8x – 6y = -4

In-s [12.5K]

Answer:

(5, - 6 )

Step-by-step explanation:

Given the 2 equations

- 8x - 10y = 20 → (1)

- 8x - 6y = - 4 → (2)

Multiply (2) by - 1

8x + 6y = 4 → (3)

Add (1) and (3) term by term to eliminate the x- term, that is

- 4y = 24 ( divide both sides by - 4 )

y = - 6

Substitute y = - 6 into either of the 2 equations and solve for x

Substituting into (1)

- 8x - 10(- 6) = 20

- 8x + 60 = 20 ( subtract 60 from both sides )

- 8x = - 40 ( divide both sides by - 8 )

x = 5

solution is (5, - 6 )

6 0

3 years ago

Y = -27x + 577, where x represents the number of weeks and y represents the amount of money left in her account. After how many

Illusion [34]

To solve this problem, plugin 145 where the y is located and then solve for x
y = -27x +577
145 = -27x +577
145 -577 = -27x
-432 = -27x
-432/-27 = -27x/-27
16 = x
x = 16
After 16 weeks she will have $145 dollars in her account.

7 0

4 years ago

Two paper drink cups are shaped like cones. The small cone can hold 6 oz of water. The large cone is 4/3 the height and 4/3 the

Ivahew [28]

B is the answer 14 is

6 0

3 years ago

Read 2 more answers

It is known that IQ scores form a normal distribution with a mean of 100 and a standard deviation of 15. If a researcher obtains

sdas [7]

Answer:

$X \sim N(100,15)$

Where $\mu=100$ and $\sigma=15$

We select a sample of n=16 and we are interested on the distribution of $\bar X$ , since the distribution for X is normal then we can conclude that the distribution for $\bar X$ is also normal and given by:

$\bar X \sim N(\mu, \frac{\sigma}{\sqrt{n}})$

Because by definition:

$\bar X = \frac{\sum_{i=1}^n X_i}{n}$

$E(\bar X) = \mu$

$Var(\bar X) = \frac{\sigma^2}{n}$

And for this case we have this:

$\mu_{\bar X}= \mu = 100$

$\sigma_{\bar X} = \frac{15}{\sqrt{16}}= 3.75$

Step-by-step explanation:

Previous concepts

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".

Solution to the problem

Let X the random variable that represent the IQ scores of a population, and for this case we know the distribution for X is given by:

$X \sim N(100,15)$

Where $\mu=100$ and $\sigma=15$

We select a sample of n=16 and we are interested on the distribution of $\bar X$ , since the distribution for X is normal then we can conclude that the distribution for $\bar X$ is also normal and given by:

$\bar X \sim N(\mu, \frac{\sigma}{\sqrt{n}})$

Because by definition:

$\bar X = \frac{\sum_{i=1}^n X_i}{n}$

$E(\bar X) = \mu$

$Var(\bar X) = \frac{\sigma^2}{n}$

And for this case we have this:

$\mu_{\bar X}= \mu = 100$

$\sigma_{\bar X} = \frac{15}{\sqrt{16}}= 3.75$

6 0

3 years ago

At Chester’s Bakery, a box of 12 donuts sells for $8.50. What is the unit price of the donuts in the box, rounded to the nearest

adelina 88 [10]

If 12 donuts cost $8.50, you can divide $8.50/12 donuts (presumably with a calculator) to get $0.7083/donut which rounds to $0.71/donut. Make sense?

7 0

3 years ago

Read 2 more answers